Open Redirect in @Backstage Plugin-Auth-Backend
CVE-2026-32235
Backstage is an open framework for building developer portals. Prior to 0.27.1, the experimental OIDC provider in @backstage/plugin-auth-backend is vulnerable to a redirect URI allowlist bypass. Instances that have enabled experimental Dynamic Client Registration or Client ID Metadata Documents and configured allowedRedirectUriPatterns are affected. A specially crafted redirect URI can pass the allowlist validation while resolving to an attacker-controlled host. If a victim approves the resulting OAuth consent request, their authorization code is sent to the attacker, who can exchange it for a valid access token. This requires victim interaction and that one of the experimental features is explicitly enabled, which is not the default. This vulnerability is fixed in 0.27.1.
Vulnerability class: Open Redirect
EPSS: 0.001 (3.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N.
Affected products
- @Backstage Plugin-auth-backend — versions < 0.27.1
- Linuxfoundation Backstage
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-32235?
- CVE-2026-32235 is a medium-severity vulnerability in @Backstage Plugin-Auth-Backend, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 5.9/10. Published 2026-03-12.
- How severe is CVE-2026-32235?
- Medium severity. CVSS v3 base score is 5.9 out of 10.